The present invention relates to a soot blower for use in a tubular heat exchanger wherein a blast of cleaning fluid such as steam is projected laterally from said soot blower over the tubes of said heat exchanger to remove deposits therefrom. Usually a soot blower itself is adapted to extend laterally through a side wall of a heat exchanger normal to a bank of tubes therein in order that a jet of cleaning fluid being ejected therefrom will pass over the tubes to be cleaned. In the case of a very long tube bank containing a dense array of tubes it is not possible to install conventional soot blowers because there is insufficient room between tubes.